Automatic circuit breaker assembly



Oct. 3, 1939. J. sAcHs l 2,174,669

AUTOMATIC CIRCUIT BREAKER ASSEMBLY Jhr/antan' osg/Uh Esau/1.5'

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Oct. 3, 1939. J. sAcHs AUTOMATIC CIRCUIT BREAKER ASSEMBLY Filed April l5, 1938 Y Y Y Y 35 parent from the Patented Oct. 3, 1939 UNITED STATES PATENT `l,OFFICE- l AUTOMATIC CIRCJZLSEAKEB ASSEMBLY Joseph Sachs, vWest to Colts Patent nccticut A Application April l5,

5 circuit breaker mechanisms or units.

'One object of t other conductor. Another object of the invention is to provide 15 an improved means for quenching or muilling lthe arcs of -a plurality of circuit breaking mechanisms. I

Another object of a circuit breaker Still other objects of the invention willbe apfollowing specification and claims.

Fig. 1 lis a front view o1' a multiple circuit breaker assembly, including a multiple housing unit, a front cover plate and a rear supporting plate. 'e

Fig. 2 is an enlarged fragmentary front view with the front cover plate removed and showing cuit breaking mechanisms in place therein.

Fig. 3 is an enlarged vertical sectional view sa taken along the lines 3 3 of Fig. 1.y

Hartford, Conn., assignor Fire Arms Manufacturing Company, Hartford, Conn.,

a corporation'of Con- 1938, Serial No. 202,297 (Cl. 175-307) Fig. 4 is an enlarged perspective view of one of the muiiler devices.

Fig. 5 is a perspective view of one of the main conductors shown in Figs.` 1 and 2 with the stationary contacts thereon.

Fig. 6 is a front view of a, single circuit breaker unit, comprising a single housing unit, a front cover plate and a rearsupporting plate.

Fig. 7 is a side View o1' the parts shfown in Fig. 6, a portion of the housing unit being broken away to show the arc muiiing device.

Fig. 8 is a view similar to Fig. 1 but showing a multiple housingY unit to show the arc muilling devices.

Fig. 10 is a perspective view of one of the main conductors shown in Figs. 8 and 9 with the stationary contacts thereon.

Fig. 11 is a front view of the multiple assembly shown in Fig. 1 mounted in van enclosing casing, parts of the casing being broken away. A Fig. 12 is a vertical sectional view taken along the line lZ-IZ'oi' Fig. 11.

Fig. 13 is a transverse sectional view taken along the line lI-IS of Fig. 11. Fig. 14 is a front view of a circuit breaker assembly including a plurality of single -housing units such as shown in Figs. 6 and 7. f

Fig'. l5 is' a transverse sectional ,view taken along the line |5-l5 of Fig. 14.

Figs. 16 and 17 are frontand side views respectively of one.of the main conductors shown in Figs. 14 and 15 with the stationary contacts thereon.

' In Figs. 1 to 5 The housing unit l Il" in .side-by-side relaf bers.

breakers, Serial No. 202,295 led large corner notch in side-by-side and end-to-endrelationship with the before-mentioned cham- The two notches in the tw'o halves ofthe unit are indicated at 5 and 5b. While the particular arrangement of chambers as shown and described is desirable and useful, I do not necessarily limit myself to this particular arrangement. For a purpose to be hereinafter explained in detail, each two chambers in end-to-end relationship, such as 4, 4Q and 4, 4f, preferably have limited communication with each other. For this purpose there are provided openings or slots I, I, The other chambers, such as 4m and Il preferably have openings or slots Ib, IJ in theirend walls.

'I'he front cover plate 3 comprises a metal plate 3' and an insulating plate 3b at the rear of the metal plate. The two plates 3 and 3b which together constitute the front cover plate s ubstantially close all of the chambers 4m, l, 4,.4P, 41, l! at the front, but are provided with openings therein through.which the handles of the several circuit breaker mechanisms can project. .rear supporting. plate comprises not only the metal plate 2 but also an insulating plate 2' at the front of the metal plate. Screws 6, 6 extend through suitable holes in the .front cover plate and ln the rear supporting plate and serve to hlolld the described parts in assembled relations p.

Similar circuit breaking mechanisms are positioned in the several chambers of the housing unit I and asl to the details of these mechanisms I do-not narrowly limit myself. However, in order that the present invention may be clearly understood I have shown and will describe mechanisms similar. to the mechanism disclosed in the co-pending application of Joseph Sachs and Paul M. Christensen for Automatic circuit on even date herewith. Fig. 3 shows two mechanisms which are identical in construction but reversed in position. In the description which'follows reference will be had chiefly to the mechanism shown A in Fig. 2 and` in the erence will also be lower part of Fig. 3, but refmadeV to the mechanism shown in the upper part of Fig.- 3 wherein the parts are in the positions which they occupy when the circuit is open.

For each mechanism tionary main contact such as 1n and also tionary conductor 8 contact. The contact 1n is rigidly mounted 'as hereinafter described. in greater detail, and the conductor 8 is mounted on the housing unit I by means of a screw 9. For each of the lower mechanisms a nut I0 on the screw 9 constitutes a wire terminal. For each of the upper mechanisms there is a separate terminal I0 connected with the corresponding conductor 8.

Directly connected electrically with each stationary conductor 8 isaflexible conductor II. For making and breaking the circuit between the contact 1n and the conductors 8 and II there is provided a contact member which is pivotally movable about a iixed axis. The said contact member comprises a conducting element I2 there is provided a staa. stalwhich carries a`movable contact I3 adapted to engage-and disengage the stationary contact- 1n. The conducting elementl metal bent so as to have a U-shape in'transverse section. The legs I2a of the U extend forward and these legs are connected at the rear by a The.

ing transverse member ing to,bias

which is separated from the` I2 is formed of sheet yoke which has an aperture I4 therein, thus providing two separated transversey yoke portions I2b and I2C. The before-mentioned movable contact I3 is carried by the transverse yoke portion I2b at the center thereof.

' For supporting the contact member and associated parts there is provided an inner frame plates I5, I5 spaced apart and which also incl'udes two transverse end plates I6 and I1. 1 In Fig. 3 the sectionis so taken as to show the right hand plate of the upper frame and to eliminate the right hand plate of the lower frame.A The end plate I6 serves to close the end of the corresponding chamber in the housing unit, and the end plate I1 serves as a partition extending across the chamber. The conducting element. I2 or the movable contact member extends through slots in the plate I1, and the plate therefor serves to separate the arcing space at the contacts from the principal portions of the circuit breaking mechanism,

The plates I5, I5 of the inner frame are connected with each other by transverse members I8, I9, 20 and 2I. The transverse member I8 is a pivot or bearing member which extends through holes in the legs of the conducting element I2, thus providing a pivotal support for the entire contact member. ber I8 is a coil spring 22' which engages the conducting element I2 and also engages the insulat- I9, this spring thus servthe contact member in the' contact disengaging or circuit opening direction. A handle or operating member 23 is pivotally supported on -the said inner frame, the transverse member znbeing utilized as the pivotal support. The operating member 23 extends forward through the corresponding opening in the front cover plate, and it is biased in the clockwise direction by aspring'u. In order that the operating member 23 may operate the contact member, there is provided a connecting mechanism which is controlled by means of a bi-metallic latch 25 bodily movable with the .contact member and cooperating directly with an actuator 26 which is mechanically connected with the operating member. The actuator 26 is pivotally mounted at 21 between the two legs I2 of the conducting element I2. The actuator 26 has a portion which extends rearward andprojects ,through .the aperture Il in the conducting element I2.

A link 28 is pivotally connected `with the op` which includes two opposite similar insulating Surrounding the memlocked or .overset toggle. The before-mentioned transverse member 2l engages a suitable shoulder on the operating member to limit movement thereof in the counter-clockwise direction.

The before-mentioned bi-metallic latch 25 normally engages the actuator 26 and holds it in its normal relationship with the other parts as shown in the lower portion of Fig. 3. The latch is rigidly secured by brazing or otherwise -to an integral downward extension I2d on the yoke portion I2c of the conducting element I2. The latch is thus connected near the pivot end of the conducting element, and it extends substanti'ally parallelly therewith to its point of engagement withthe actuator 2t. The beforelus near the upper latching end thereof. 'Ihis con-v nection may be effected by brazing.

The stationary contact ,1 is rigidly supported and the before-mentioned link 28 is U-shaped and resilient so as to 'be vadapted to yield as the toggle approaches its overset relationship, and the link thereupon serves to apply to the contact member the force`necessary to provide the required pressure between the contacts. The force exerted by the link also normally serves to hold the toggle in overset relationship.

With the circuit breaker in closed-circuit position as shown in the lower portion of Fig 3, it

will be apparent that electrical connection is established from the stationary contact 1 to the movable contact |3, thence vthrough the conducting element |2 and the bi-metallic latch 25, 'and thence through the flexible conductor I to thel stationary conductor 8. contact member is biased in the 'circuit-opening direction by 'means of the spring 22, and the operating member is biased in the clockwise or by means of the spring circuit-opening direction 24. However, actual movement vin the circuitopening direction is normallyprevented by reason ef the described overset toggle relationship between theA operating member itself and the link 28', it being understood that the latch 25 normally holds the actuator. 26 from relative move- As already stated, thev ment in the clockwise direction. Normally the operating member 23 may be moved to move the contact member and thus open or close the -circuit. During such normal movements the latch 25 remains engaged with' the actuator 26.

Ifthe handle or 'operating member be held in its closed-circuit position as shown in the lower portion of Fig. 3 and if an abnormal current condition such as an'overload is attained, the bimetallic latch 25 is automatically deflected rearward so as to disengage and release the actuator This deflection ordinarily occurs chiefly by reason of the heating of the bi-metallic element. When the actuator `is no longer held by the latch x25, the entire contact member is moved by the spring 22 to its open-circuit position this movement occurring even though the handle be held in closed-circuit position. Ordinarily, however, the. handle is not held and the spring 24 moves l the operating member to the position shown in the upper portion of Fig. 3, this'in turn moving the link 28 and the actuator 26 to the .positions there shownmember andthe actuator occurs as soon as the actuator has moved far enough to break the locking relationship between the operating member 23 and the link 28. All of the parts thus move practically instantaneously to the positions shown in the upper portion of Fig, 3, the actuator being immediately restored to engaging relationship with the latch. As soon as the latch has cooled sufllciently the operating member can be moved to again fclose the circuit.

In accordance with the present invention, the stationary contactr 1 isv carried by or mounted directly upon a. main conducting means, such as a conductor 29, and the contact is free from any permanent or direct connection with the housing unit li The housing unit has an opening in one cover plate has been 'I'his movement of the operating exterior of the wall thereof and the conducting means has a of the housing unit, and the' of the unit, as shown and described, the conducserves as a' bussing conductor' and has 'three forward projecting portions which carry three suitably' spaced stationary contacts 1n, 7m, '.L Preferably andas shown the rear wall of the housing unit has a recess Vfor receiving the conductor 29B and the said conductor is clamped between the housing unit and' the rear supporting plate and is tl'ius heldin place. A wire terminal 3|!a is connected with the bussing'conductor 29a and is positioned in the notch 5B. A bussing conductor 29b is provided at the left, this, carry-ing contacts 1, 1P, lr and being provided with a wire terminal 30b in the not'chb. It will be observed that the 'housing unit and the conductor 29 and 29'" are without positive connection with each other except through the supporting plate, and that when detached from the supporting plate they are readily separable from each other. When the contact carrying portions of the conductors project forward through openings in the rear walls of the units separation is effected by relative forward or rearward movement. f f Preferably an arc mailling device is. positioned in each chamber adjacent the partition plate Il and in the main at the front of the two contacts.

'The arc mufiling device may be a separate structure normally held in place by the front ycover plate, but -being removable as a unit after the removed. The arc muii'iling device is preferab'y so constructed as' to provide a circuitous passageway for the gases, and when the contacts are near the rear the passageway may advantageously extend in a generally for- 'ward direction.

The arc muffling devive as shown 'in the drawings comprises an insulating sheet 3| bent to provide a rear wall 3|n and two opposite parallel There yis also provided a transverse insulating ably separate from the sheet- 3|. The rear wall 3|"L has an opening 3|c therein through which projects theportion of the bussing conductor carrying the corresponding stationary contact. Carried by the opposite walls 3|, 3|b are metallic plates 33, 33 oppositely positioned so as to provide a circuitous or serpentine passageway as clearly shown in Fig. 3. Preferably the side walls 3|b, 3|b have slots or apertures therein in which are seated the end portions of the plates 33, 33. The side walls of the chamber in the housing unit preferably have opposite grooves for the ends of the plates 33, 33.as shownnin Fig. The opposite side walls of the arc m'uiliing device have notches 3|, 3|d therein and the transverse end wall, 32 has a notch 32* therein. The main body of the housing unit has transverse notches I, |c at the front registering with the notches 3| d, 3|d. 'I'nese notches communicate either with the unit or with the next adjacent chamber. v

Whe'n there are mechanisms in two chambers suchras ln-and 4'1 in end-to-end relationship, the end walls 32, 32 of -the arc muilling devices preferably have openings or slots 32h, 32b therein in register with the corresponding opening or s lot |u in the housingstructure. is interrupted at the contacts a portion of the gases move through the circuitous passageway provided by sheet 32, which is preferthe plates' 33, 33 of When the circuit of one mechanism,

' 'the corresponding another portion of the gases move through the corresponding arc muiiling device Vthe multiple housing unit 'I.

arc mulillng device, and

slots 32h, I, 32h into the are ufiling device of the adjacent mechanism vand then through the circuitous passageway therein. The interconnection of the two arc muilling devices makes it possible to utilize both of them and to .thus obtain' greater gas dispensing or cooling eiliciency. When a chamber such as 4m or 4q has no other chamber in end-to-end' relationship there may bea slot b in the end wall of the chamber, as already stated, but the end wall 32 of the does not have a slot 32b therein. When the mechanism' is in a chamber such as- 4In or 4P without another chamber, in end-to-,end relationship therewith, all of the gases formed as'the result of the separation of the contacts are forced to move through the corresponding circuitous passageway.

Whilethe invention is particularly applicable to a multiple circuit breaker assembly such as shown in Figs. 1 to 3 it is. also to some extent 'applicable toa single unit as shown in Figs. 6 and 7. The single housing unit 34 shown in these figures has an open-front'lchamber therein of the same size and shape as the chambers in There is a rear supporting plate 35 comprising-a metal plate 359 with an insulating plate b thereon, and there is also a front cover plate 36 comprising a metal plate 36B and an insulating plate 36h. Screws 31, 31 serve to hold thedescribed parts in assembled'relationship. By means of the supporting plate 35 the entire unit can be mounted on asuitable supporting wall, such as the rear wall of an enclosing casing.-

-A stationary contact 38 is carri-ed by a forward projecting portion of a conductor 39 which is a wire terminal 46.' The conducl formed in the back of the housing unit 34 and it is clamped between the housing unit and the supporting plate. The circuit breaker mechanism may be identical in construc- .tion with that already shown and described.

The arcmuiiling device maybe the same as that already described, but itwill be observed that inasmuch as there is no other unit in endto-end 'relationship with the unit shown, the end wall 32 of the muiliing. device does not `have a slot 32b therein. However, the end wall. of the housing may have a slot 34l therein, which makes 'the housing unit more suitable for u se in combination with other units. In Figs. 8, 9v and 10 there is shown a circuit breaker. `assembly which is similar to that .shown in Figs. 1v to 3 but which differs in that there are eight mechanisms instead of' six. The main housing unit, I- and the reary supporting plate 2 may be identical in construction with those as shown in Figs. mechanisms may be identical in' construction. In order to provide eight mechanisms instead of six, two single housing units 34, 34 are located in the notches 5, 5b of the housing a larger front cover plate 4| is provided, adapted to cover all of the units and cooperate with all of the eight mechanisms. Bussing conductors 42, 42 are provided which are similar to the bussing conductors them carriesfour stationary contacts instead of three, the wire terminals 43, 43Il being positioned at the sides of the assembly. The bussing conductor 42 as shown in'Flg. 10 carries four contacts 1m, 1, 1I and 1.

The arc muiiling devices at the sides, as for instance those at the right side as' shown in tor is in a recess engaging means .1 to 3, and the circuit breaking unit I. andf 28' and 28b'excep't that 'each of- Y tralwires.

Fig. 9, function exactly as already described in connection with Figs.1 to 4. Inasmuch as there are two units in end-to-.end relationship, the muffler plates 32, 32 have slots 32D, 32b therein as shown, thus permitting the gases to. pass from o ne muiiiing devicelto the other through the slots 32h, 1, 34, 32h.

' It will be observed that by providing six-mechanism housing units such as l 'and single mechanism housing units such as 34, and by providing tw'o different styles of front plates such as 3 and 4I, andby providing two different styles of bussingI conductors such as 29, 29b and 42, it is` possible to manufacture at a minimum cost either a six-unit circuit breaker assembly as shown in Fig'. 1,'or an eight-unit circuit breaker assembly as shown in Fig. 8. j

The supporting plate for the circuit breaker assembly, such as the plate 2, can be mounted in a variety of ways and one suitable way is shown in Figs. l1 to 13. As shown, the entire assembly means of the plate 2, in an enhas an openable front cover 45 secured by screws 46, 46, the said cover preferably having a central depressed cover' project the operating members or handles of the several mechanisms.

Brackets 41, 41 project forward from the rear wall of the casing 44, these brackets being near one edge of the supporting plate, as for instance the top edge. Interengaging means on the brackets and on the supporting plate enable the latter to be detachably hinged to the former. 'As shown, the brackets 41, 41 have slots 41 adapted to receive laterally projecting ears 2B, 2- on the plate 2 near the top edge thereof. Other brackets 48, 48 project forward fromthe rear wall of the casing, these brackets being near the opposite edge ofthe supporting plate, i'n the present instance near the bottom edge. Interon the brackets 48, 48 and on the supporting plate enable the latter to be snapped into or outl of connected relationship withthe former. As shown, the brackets 48, 48 are provided with slots 48? adapted to receive other laterally projecting ears 2b, 2b on the plate 2 near the bottom edge thereof. In connecting the circuit breaker assembly with the casing, the rst entered in the slots 41 and then the entire assembly is swung rearward to enter the ears The last said slots are slightly narrower than the ears and have shallow notches in their sides so that the said ears, after being forced into the slots, will be firmly By' applying force in the forward direction the ears 2b, 2b can be disengaged and the entire assembly can be removed.

The brackets 41, 41 and 48, 48 are of sumcient length to detachably hold the plate 2 at a suitable predetermined distance from the rear wall of the casing. Thus there is provided ample wire receiving space at the rear of the plate. If more convenient, soieor all'of the wires can be put in place before-the circuit breaker assembly is mounted in the casing. Suitable. provision'is made at 49 for .the connection of neu- In Figs. 14 to 1'1 there is shown a circuit'breaker assembly wherein a plurality of single housing units, such as 34, 34, are connected directly with the rear wall o f an' enclosing casing .58. They are separated from thecasing wall by an insulating but yieldably held at the notches..

i sheet l.

4units in the respective rows are in end-to-end re- The units are in two rows and the A front cover plate 52 is provided of suitable size to cover and cooperate with -all o'f the units and screws 53, 53 extending through the plate serve to hold the several housing units in place. The casing 50 has a front cover-5I with a central depressed -portion 54- having openings for the several operating members or handles.

Preferably the units ot the two rowsare separated by 'an insulating sheet 55. conductors 56 and ,5l extend transversely of the units and are positioned in the several recesses in' the backs thereof. They are clamped between the housing'units and the rear wall of the casing. These conductors have'suitably spaced forward extending portions carrying stationary contacts 58 and 59 adapted to cooperate with the movable contacts of the several mechanisms. The conductors arevprovided respectively with wire terminals 60 and Bl. Suitable provision is made at 62 for the connection of neutral wires.

The action of the arc muilling' devices is as shown in Fig. 9. In order to provide a passageway from one arc muilling device to another the insulating sheet 55 may be provided with suitable slots or holes (not shown) registering with the several slots 34a in the housing units.

What I claim is:

1. In an automatic circuit breaker, the combination of a housing having a wall with an opening therein, an automatic circuit breaking mechanism located chiefly within the 'housing and having a contact which is movable to open and close the circuit and which .when in closed-circuit position is adjacent the said opening in the housing wall, a conducting means positioned in part outside of the housing and having a portion which projects into the housing through the said opening, and a stationary contact carried by the projecting portion of the conducting means in position to be engaged by the movable contact when in closed-circuit position, the said conducting means and the said contact thereon being free from any direct connection with the housing and being so related to the said housing opening that they can be readily withdrawn from 'the housing by movement relative Ithereto while remaining in fixed relation to each other.

` 2. In an automatic circuit breaker, the combination of 4 a housing 'having 'a wall with an opening therein, an automatic circuit breaking mechanism located chiey within the housing and having a contact which is movable to open and close the circuit and which when in closed-circuit position is adjacent the said` opening in the housing wall, a conducting means positioned .in parts outside of the housing and having a portion which projects, through and substantially ts and lls the said opening in the housing wall, and a stationary contact carried by the projecting portion of the conducting means in position to be engaged by the movable contact when in closed-circuit position, the said conducting means and the said contact thereon being free from direct connection with the housing and being so related to the said housing opening that they can be readily withdrawn from the housing by movement relative thereto while remaining in fixed relation-to each other. s

3. In an automatic circuit breaker, the combination of a housing having a rear wall with an andclose the circuit and which when in closedcircuit position is adjacent the said opening in the rear wall, and a conducting means positioned at the rear of the housingand having a portion which projects forward through the. said opening in the housing rear wall and which carries at its forward end a stationary contact in position to be engaged by the movable contact when in closed-circuit position, the said housing and the said conducting means with thev contact thereon being readily separable from each other by relative forward or rearward movement.

.4. In an automatic circuit breaker, the combination of a housing having a rear Wall with an opening therein, an automatic circuit breaking I mechanism located chiefly within the housing and having a movable contact which is movable to open and close the circuit and which when in closed-circuit position is adjacent the said opening in the rear wall, a rear supportfor the housing, means for connecting the housing with the said rear support, and a conducting means positioned at the rear of the housing and having a portion which projects forward through the said opening in the housing rear wall and carries at its forward end a stationary contact in position to be engaged by the movable contact when in closed-circuit position, the said conducting means being engaged by and clamped between the housing and the rear support and the said housing and thesaid conducting means with the contact thereon being readily separable from each other by relative forward or rearward movement when the housing is disconnected from the support.

5. In an automatic circuit breaker assembly, the combination of a housing structure having a plurality of similar chambers therein and having a plurality of wall openings associated with the respective chambers, a plurality of automatic circuit breaking mechanisms respectively loca-ted chieily within the several chambers of the housing structure and having contacts which are movable to open and close corresponding portions of the circuit, and a single conducting means positioned in part outside of the housing structure and having a plurality of portions which project into the housing structure through the respective openings, and a plurality of stationary contacts carried by the respective projecting portions of the conducting means in positions to be engaged by the respective movable contacts when in closed-circuit positions, the said conducting means and the said contact thereon being free from direct connection with the'housing structhe combination of a housing structure having a plurality of similar chambers therein and having a plurality of rear wall openings associated with the respective chambers, a plurality of automatic circuit breaking mechanisms respectively located chiefly within the several chambers of the housing structure and having contacts which are mov-` able to open and close corresponding portions of the circuit, and a single conducting' means positioned. at the rear of the housing structure and having a plurality of portions which project forward through the respective rear wall openings in the housing structure and which carry at their forward ends stationary contacts in positions to when in closed-circuit positions, the said housing structure and thesaid conducting means with the contacts thereon being `readily separable from each other by relative forward or rearward movement. s

'7. In an automatic circuit breaker assembly, the combination of a housing structure having a plurality of similar chambers therein and having a plurality'of rear wall openings associated with the respective chambers, a plurality of automatic circuit breaking mechanisms respectively located chiefly within the several chambers of the housing structure and having contacts which are movable to open and close corresponding portions of the circuit, a rear support for the housing structure, means for connecting the housing'I structure with the said rear support, and a single conducting means positioned at the rear of the housing structure and having a plurality of portions which project forward through the respective rear wall openings in the housing structure and which carry at their forward ends stationary contacts in positions to be engaged by the respective movable contacts when in closed-circuit positions, the said conducting means being engaged by and clamped between the housing structure and the rear support, the said housing structure and the said conducting means with the contacts thereon being readily separable from each other by relative forward or rearward movement when the 'housing structure is disconnected from the support.

In an automatic circuit breaker assembly, the combination of a housing structure comprising two or more separable units 'and having a plurality ofv similar chambers in the respective units,

`the units-of the housing structure having a plurality of rear wall openings associated. with the respective chambers, a'plurality of automatic circuit breaking mechanisms respectively located chiefiy within the several chambers of the said units and having contacts which are movable to open and close corresponding portions of the circuit, and a -single conducting means positioned at the rear of the housing structure units and having a plurality of portions which project forward through the respective rear wall openings` in the units and which carry at their forward ends stationary contacts in positions to be engaged by the respective movable 'contacts when in closed-circuit positions, the said housing structure units and the said conducting means with the contacts thereon being readily separable from each other by relative forward or rearward movement.

9. In an automatic circuit breakerassembly, the combination of a .housing structure having at least two similar chambers therein in end-to-end relationship and having at least two rear wall openings associated with the respective chambers near the adjacent ends thereof, at least two oppositely positioned automatic circuit breaking mechanisms respectively located chiefly within 'the corresponding chambers ofthe housing structure and having contacts which are movable to open and closecorresponding portions of the circuit, and a single conducting means positioned at the rear of thehousing structure and having at least two portions which project forward through the respective rear wall openings in the housing structure and which carry at their forward ends stationary contacts in positions to be engaged by the respective movable contacts when in closedcircuit positions, the said housing structure and munication with each move through the circuitous passageway of the of the circuit, the contacts of the respective mechthe said conducting meanswith the contacts thereon being readily separable from each other by relative forward or rearward movement.

10. An automatic circuit breaker assembly comprising in combinatio ing two similar chambers therein in end-to-end relationship which chambers have limited comother at their adjacent ends, two automatic circuit breaking mechanisms located chiefly within the respective chambers of the housing structure and each having .two contacts relatively movable to open and close two portions of the circuit, the contacts of the respective mechanisms. being located within and near the adjacent communicating ends of the chambers, and means in the respective chambers and near the adjacent ends thereof for forming circuitous passageways separate from the main portions of the chambers so that upon separation of the contacts of either mechanism to open the circuit one portion of the arc-formed gases will corresponding chamber and another portion of the said gases will enter the other chamber and move through the circuitous passageway thereof.

11. An automatic circuit breaker assembly comprising in combination, a housing structure having two similar chambers therein in end-to-end relationship which chambers have limited .communication with each other at their adjacent ends, two automatic circuit breaking mechanisms located chiefly within the respective chambers of the housing structure and each having two contacts relatively movable to open and close two portions of the circuit,'the contacts of the respective mechanisms being located near the adjacent communicating ends of the chambers and near the rear thereof, and means in the forward portions of the respective chambers and near the adjacent ends thereof for forming circuitous passageways separate from the main portions of the chambers so that upon separation of the contacts of either mechanism to openthe circuit one portion of the arc-formed gases will move in a generally forward direction through the circuitous passageway of thecorresponding chamber and another portion of the said gases will enter the other chamber and move in a generally forward direction through the circuitous passageway thereof.

12. An automatic circuit breaker assembly comprising in combination, a housing structure having two similar chambers therein in end-to-end relationship which chambers have limited communication with each other at their adjacent ends and are otherwise substantially closed except at the front, a front cover means substantially closing both chambers at the front, two automatic circuit breaking mechanisms located chiefly within the respective chambers of the housing structure and each having two contacts relatively movable to open and close two portions anisms being located near adjacent communicating ends of the chambers and the principal por- 6- tons of the mechanisms being readily movable in the forward direction upon removal of the front cover means, and arc muffiing devices in the respective 'chambers near the adjacent ends thereof and readily movable in the forward direc- 7 tionupon removal of the front cover means, the said arc muilling devices having means forming circuitous passageways separate from the main portions of the chambers so that upon separation of the contacts ci either mechanism to open the 'I a housing structure hav- 5 circuit one portion ofthe arc-formed gases will extending through' the corresponding opening move through thecircuitous passageway of the in the front plate.4 'corresponding chamber and. another portion of 16. The combination in an automatic circuit the said gases will enter the other chamber and breaker assembly, of a housing comprising a plumove through the circuitous passageway thereof. rality of separable, units and having in the re- 5 13. An automatic circuit breaker assembly comspective units a plurality of similar open-front prising in combination, a housing structure havchambers, a single unitary plate substantially ing.two similar-chambers therein in end-to-end closing all of the chambers of all units but hav- 10 tionwith each other at their adjacent ends, two fronts of the chambers, a plurality 0f supporting 10 of the circuit, the contacts ofthe respective mechplurality 0f automatic circuit breaking `Ineeha- 15 zo'with registering openings therein, the said arc and each 0f them Serving uDOn the attainment 20 muiiling devices having means forming circuitous of excess current conditions to break that porpassagcways separate from the main, portions of tion of the lcircuit; in which it is connected and portionof the arc-formedgases will move through responding Opening in .the front Plate. 25

the circuitous passageway 0f the corresponding 17. The combination in an alltOmatC Circuit chamber and yanother portion of the said gases breaker assembly. 0f a. hOuSihg Structure ccmtous passageway there() front chambers, a single unitary plate substan- 80 14. An automatic circuit breaker assembly comtialiy closing all 0f the chambers 0f all units but prising in combination, a housing stucture comhaving a piuraiity- 0f handle Openings therein being located with their chambers in end-to-end bers and ,behind and nengagement With the 35 ing mechanisms located chiefly within the respecframes end freely lnoVeble ln the 'forward dileC- 40 cated near adjacent communicating ends of the l to break that Portion, 0f the Circuit in Which it iS 45 of the contacts of either mechanism to open the of the housing units at the rear thereof, connec- 50 cir-cintoneportion o'f the arc fonned gases will tion devices extending from the front plate to the move through the circuitous passageway of the reel' Supporting plete and Serving to hold the corresponding chamber and another portion of plates in xed relation to each other and to all the said gases will enter the other` chamber an'd of the housing units' end Ineens on the Teal' SUP- move through the circuitous passageway thereof.. Porting Plate whereby lt may he independently 55 l 15. The combination in an automatic circuit Secured t0 a Stationary rear. wallhreaker assembhnof a housing structure having 18. The combination in an automatic circuit therein a plurality lof similar open-front chambreaker assembly of a' houslng Structure oom' bers, a single unitary 'plate substantially closing Plslngtwo separable units one of the Said units 2111,01 the chambers at the front but having a having therein three similar open-front cham- 60 plurality of handle openings therein, a plurality bers With two of thenl n Sldebysde relationof supporting frames positioned in the respective ship and with the third in end-to-end relationhousing chambers and behind and in engagement Ship With One 0f the first tWO and the Said unit ward direction, anda plurality of automatic cir- Said unit and having therein a single open-front cuit breaking mechanisms carried chljey by the Vchamber similar to the chambers inthe nrst said respective frames and freely movable in the forunit and in side-by-side and end-to-end relationship with them, front cover means substantially the said mechanisms being connectible in differclosing all of the chambers of both units but 70 ent portions of the circuit and each of them servhaving a plurality 0f handle Openings therein at ing upon the attainment of excess current conthe fronts of the chambers, and a plurality of ditions'to break that `portion of the circuit in automatic circui" breaking mechanisms 'located which it is connected and each of the said mechchi .ziiy within the respective chambers and con- '5 anisms havinlir a movable handle at the front nectible in different portions of the circuit, each of the said mechanisms serving upon the attain- V19. The combination -in an automatic circuit breaker assembly, of a housing structure comprising two separable units, one of the said units having therein three similar open-front chambers with two of them in side-by-side relationship and with the third in end-to-end relationship with one of the first two and the said unit having a notch therein' and the other of the said unitsbeing positioned in the notch in the first said unit and having therein a single open-front chamber similar to the chambers 'in the first said unit and in side-by-side and end-to-end relationship with them, a single unitary plate substantially closing all of the chambers of both units but having a plurality of handle openings therein at the fronts of the chambers, and a.

plurality of automatic circuit breaking mechanisms located chiefly within the respective chambers and connectible in different portions of the circuit, each of the said mechanisms serving upon the attainment of excess current conditions to break that portion ofthe circuit inv which it is connected and each of the said mech-l anisms .having a movable handle at the front extending through the corresponding opening in the front plate.

20. The combination in an automatic Acircuit breaker assembly, of a housing structure comprising two separable units, one of the; said units having therein three similar open-front chambers with two of them in side-by-side relationship and with the third in end-to-end relationship with one of the first two and the said unit having a notch therein and the other'of the said units being positioned in the notch in thefirst said unit and having therein a single open-front chamber similar to the chambers in the first said unit and in side-by-side and end-to-end relationship with them, a single unitary plate substantially closing all of the chambers of both units but having a plurality of handle openings therein at the fronts of the chambers, a-plurality of supporting frames positioned in the respective housing structure chambers and behind and Ain engagement with the front plate and being, otherwise freely movable in the forward direction, and a plurality of automatic circuit breaking mechanisms located chiefly within the respective chambers and carried chiefly by the frames, the saidl mechanisms 'being freely movable in the forward direction when the frames are lso moved and being connectible in different portions of the circuit and each of the said mechanisms `serving upon the attainment of excess current conditions to break that portion of the cir- 4 is connected and each of the said mechanisms having a movable handle at the front extending through the corresponding opening in the front plate.

21. The combination in an automatic circuit breaker assembly, of an insulating housing structure, a plurality of automatic mechanisms carried by-the housingstructure and connectible indifferent portions of the circuit and each of them serving upon the attainment of excess current conditions to break that portion of the circuit in which it is connected, a supporting plate to which' the housing structure is connected at the rear, a rear wall behind the supporting plate, brackets projecting forward from the rearwall near on'e`edge of the supporting plate, interengageable means on .the

brackets-and on the supporting plate enabling the latter to be detachably hinged to the former, other brackets Aprojecting forward from the rear wall near the opposite edge of the supporting plate, and interengageable means on the last said brackets and on the supporting plate enabling the latter to be snapped into or out of connected relationship with the former, the supporting plate when hinged to the first said brackets and when in connected relationship with the second said brackets being detachably held at a predetermined distance in front of the rear wall.

JOSEPH sAcHs respective circuit breaking 

